Cyclic malonaldehyde diacetals



United States Patent Ofilice ,223, 3 CYCLIC MALONALDEHYDE DIACETALSGeorge Kesslin,Te aneck, N.J., and Robert W. Handy, 'Stony Point, andJames Steinmetz, Congers, N.Y., assignorsto Kay-Fries Chemicals, Inc.,West Haverstraw,

.Y., a corporation of New York No Dra ing- Filed July 2, 1 6 Sen. No.292,4 6., 4 Claims. (Cl. 260-338) This invention relates to novel cyclic,diacetals of malonaldehyde and to the method of their preparation. Moreparticularly, the invention concerns such diacetals derived fromaliphatic polyols containing from 4 to 6 carbon atoms.

The cyclic malonaldehyde diacetals of the invention have the generalformula:

wherein X is selected from the group consisting of H and CH and X isselected from the group consisting of H, HO(CH N and NH and n may varyfrom 0 to 2. Thus, when n is 0, X is H and X is HO(CH when n is 1, X isCH; and X may be N0 or NH and when n is 2, X and X are both H.

The cyclic diacetals of the invention may thus be considered asdioxolane, dioxane, or dioxepane derivatives, depending upon whetherthere are two, three or four carbon atoms between the two oxygen atoms.They are prepared preferably by transacetalization of a lower molecularweight malonaldehyde diacetal with a selected aliphatic polyol in thepresence of a Lewis type acid as a catalyst, such as, for example, borontrifiuoride etherate, in accordance with conventional procedures.

The novel compounds of the invention differ from previously knowncompounds of this type in two respects. First, they are diacetals ofmalonaldehyde, rather than acetals of glyoxal or of glutaraldehyde.Second, they differ in the structure of the aliphatic carbon chain whichlinks the two cyclic oxygen atoms.

There are employed as starting materials in accordance with theinvention, straight or branched chain saturated aliphatic polyols, whichmay be substituted by nitro, amino, or hydroxy groups, and which containfrom 4 to 6 carbon atoms. Examples of such starting compounds include:

Butane diol-1,4

Hexane triol-1,2,6 2-nitro-2-methyl propane diol-1,3 2-amino-2-methylpropane diol-1,3

but the invention is not limited to the use of these specific startingmaterials.

The aforementioned starting materials are reacted with a lower molecularweight malonaldehyde diacetal, such as, for example, malonaldehydetetramethyl diacetal, malonaldehyde tetraethyl diacetal, ormalonaldehyde trimethyl monoethyl diacetal, the aliphatic polyol beingin slight (2% to molar excess, in the presence of boron trifluorideetherate as catalyst, preferably in presence of an organic solvent. Thelower molecular weight alcohol formed by the transacetalization reactionis distilled off, preferably under vacuum, the catalyst neutralized with3,223,713 .Rstente 14, 5

2 sod m ethylate. a d the stu s re ction mix ure. di t l e unde h gh'acuum- The result n Product a e ma n crystalli e solids a r om em ra ue.

The novel ,rna o aldehyded ce als of the nvention a e e u a ss-l n la tsf r sy th t c e in PIQ' w s. nd ce lu e ic ma ia s. The ii-a e al whi hta n dr x r s an s v as mod fier f e xy nd ur ha s. and as y c r ers or.h llnqintp i nks- The diacetals react with water and can be employedfor s v ng traces Of mo s u uch a o cur .f l xam le, in transformeroils, without leaving deleterious residues or adversely affecting thequality of the oils.

The following examples serve to illustrate the prepara tion andproperties of the novel diacetals of the invention, but are not to beconsidered as limiting:

EXAMPLE 1 Diacetal derived from butane dial-1,4

1 molecular equivalent of malonaldehyde trimethyl monoethyl diacetal 178grams, were dissolved in about 750 cc. of toluene, and there were addedto the solution from 2% to 5% in excess of 2 mols of butane diol-1,4,and from about 025 to 2 cc. of boron trifluoride etherate per mole oftrimethylmonoethyl diacetal. Distillation over a still head was startedimmediately under a vacuum of 15 to 28 inches to maintain the liquidtemperature below about 1l21l3 C. When all the low boiling alcoholsformed had been removed by distillation as azeotropes with toluene, thecatalyst was neutralized with a volume of sodium ethylate (12.5% Na)equal to four times the volume of boron trifiuoride etherate used. Thecrude reaction mixture was then distilled under high vacuum (0.5 to 2.0mm.), forecuts being taken as necessary, to recover toluene and. thenthe product.

The resulting diacetal had a melting point of 36 C., and a boiling pointof 107-109 C. at 0.8 mm., and had the analysis C 62.88%; H 9.62%; 017.50% and the probable structural formula:

EXAMPLE 2 Diacetwl derived from 2-m'tro-2-methyl-pr0pane dial-1,3

probable structural formula:

C113 CH1 O 0-011, CH3

CH-CHrCfi o NO2/(IJHZO O-IENO2 dried at room temperature.

3 EXAMPLE 3 Diacetal derived from Z-amino-Z-methyl-propane dial-1,3

220.5 grams of the diol were added to 685 grams of isopropanol(representing a 5% molar excess over 2 mols per mol of malonaldehydeacetal reactant). Dry HCl was passed into the solution forming a slurryof the HCl salt of 2-amino-2-methyl-propane diol-1,3. Then there wasadded 178 grams of malonaldehyde trimethyl monoethyl diacetal at roomtemperature and the reaction mixture was heated under reflux at 8082 C.At 60- 65 C. all solid passed into solution and after about /2 hourunder reflux the product started to precipitate. Re fluxing wascontinued for a total of 2 hours, when the reaction mixture. was cooledand the product filtered 01f and washed with 2-50 cc. portions ofisopropanol and air There were obtained 162 grams of a light yellowproduct corresponding to a yield of 50.8%. Refluxing the filtrate for anadditional 10 hours increased the yield by 11.8 grams or 3.7%, makingthe total yield 54.5%. The product had a melting point of 223 C. andanalyzed C 39.90%; H 8.04%; N 7.95%; 0 44.11%; and its probablestructural formula was:

EXAMPLE 4 Diacetal derived from hexanelriol-1,2,6

pared by a procedure similar to that of Example 1. The resulting producthad a melting point of 935 C. and a boiling point of 202212 C. at 0.2mm. pressure. The compound analyzed C 59.26%; H 9.50%; 0 31.24%. Itsprobable structural formula is:

I 2-methyl-propane-diol-1,3.

3. The cyclic diacetal of malonaldehyde and 2-amino-Z-methyl-propane-diol-1,3

4. The cyclic diacetal of malonaldehyde and hexanetriol-l,2,6.

References Cited by the Examiner Rondestvedt, J. Org. Chem., vol. 26,pp. 2247-53 (1961).

WALTER A. MODANCE, Primary Examiner. NICHOLAS S. RIZZO, Examiner.

1. THE CYCLIC DIACETAL OF MALONALDEHYDE AND BUTANEDIOL-1,4.